Dresser

ABSTRACT

A dresser includes an attachment secured to a dresser shaft for rotating the dresser, a disk holder removably attached to the attachment by a magnetic force, and a dresser disk removably attached to the disk holder. The dresser disk has a dressing surface. Each of the attachment and the disk holder has magnet for generating the magnetic force.

CROSS REFERENCE TO RELATED APPLICATION

This document claims priority to Japanese Application Number 2012-219304 filed Oct. 1, 2012, the entire contents of which are hereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a dresser for dressing (or conditioning) a polishing pad of a polishing apparatus which is typified by a CMP (Chemical Mechanical Polishing) apparatus.

2. Description of the Related Art

A CMP apparatus for use in semiconductor fabrication is an apparatus for polishing a water. This CAP apparatus is configured to polish a surface of a wafer by bringing the wafer into sliding contact with a polishing pad while supplying a polishing liquid onto the polishing pad. As the polishing pad polishes wafers, the polishing pad gradually loses its polishing performance. Therefore, a dresser is typically used to restore a surface of the polishing pad by slightly scraping away the surface of the polishing pad.

The dresser has a dresser disk for dressing a polishing surface of a polishing pad. This dresser disk has a pad contacting surface constituted by diamond abrasive grains, which are placed in sliding contact with the surface of the polishing pad to thereby scrape the polishing pad. The dresser disk itself is made of any of various materials including a corrosion-resistant nonmagnetic material such as SU316, a corrosion-resistant magnetic material such as SUS630, and a resin such as polycarbonate. A brush dresser having an implanted brush, instead of the diamond abrasive grains, may be used.

The dresser disk and the brush dresser are consumables, and are therefore inspected and replaced regularly. In order to facilitate the replacement of the dresser, the dresser disk may be made of a magnetic material. This is for the reason that a disk holder, which is for holding the dresser disk and having magnets embedded therein, can hold the dresser via a magnetic force. Such a removable structure using the magnetic force is very convenient because it requires no tools ibr replacing the dresser disk.

However, this conventional removable structure with use of the magnets is not applicable to a dresser made of a nonmagnetic material, such as a resin or the like. In recent years, there has been a demand for using a plastic material for the dresser, from viewpoints of corrosion resistance and prevention of metal contamination. Further, it is necessary to remove the disk holder When replacing the brush dresser and the diamond dresser. Accordingly, there has also been a demand for better ease of the replacement.

SUMMARY OF THE INVENTION

In view of the above situation, it is an object of the present invention to provide. a dresser which can simply be replaced regardless of the type of material of the dresser.

In order to accomplish the above object, a first aspect of the present invention provides a dresser for dressing a polishing pad, comprising: an attachment secured to a dresser shaft for rotating the dresser; a disk holder removably attached to the attachment by a magnetic force; and a dresser disk. removably attached to the disk holder, the dresser disk having a dressing surface, wherein each of the attachment and the disk holder has magnet for generating the magnetic force.

In a preferred aspect of the present invention, the magnet comprises a plurality of magnets arranged around a center of the dresser; and an arrangement of the plurality of magnets are such that magnetic poles of adjacent two of the magnets are different from each other.

In a preferred aspect of the present invention, the plurality of magnets constitute a plurality of groups arranged at equal intervals around the center of the dresser, each of the groups includes at least three magnets arrayed such that north pole and south pole. alternate with each other, and an arrangement of the at least three magnets is the same in all of the plurality of groups.

In a preferred. aspect of the present invention, the attachment is removably secured to the dresser Shaft..

In a preferred aspect of the present invention, the dresser disk is removably attached to the disk holder.

In a preferred aspect of the present invention, the dresser disk is attached to the disk holder by a magnetic force.

In a preferred aspect of the present invention, the dresser disk is attached to the disk holder by a screw.

A second aspect of the present invention provides a dresser for dressing a polishing pad, comprising: an attachment secured to a dresser shaft for rotating the dresser; and a brush disk removably attached to the attachment by a magnetic forces, the brush disk having a dressing surface, wherein each of the attachment and the brush disk has magnet for generating the magnetic force.

In a preferred aspect of the present invention, the magnet comprises a plurality of magnets arranged around a center of the dresser, and an arrangement of the plurality of magnets are such that magnetic poles of adjacent: two of the magnets are different from each other.

In a preferred aspect of the present invention, the plurality of magnets constitute a plurality of groups arranged at equal intervals around the center of the dresser, each of the groups includes at least three magnets arrayed such that north pole and south pole alternate with each other, and an arrangement of the at least three magnets is the same in all of the plurality of groups.

In a preferred aspect of the present invention, the attachment is removably secured to the dresser shaft.

According to the first aspect of the present invention, the attachment and the disk holder are simply attracted to each other by the magnetic force. Therefore, the disk holder, together with the dresser disk, can be removed from the attachment relatively easily by hand. Because the dresser disk is held by the disk holder, the present invention can be applied regardless of whether the dresser disk is made of a magnetic material or a nonmagnetic material.

According to the second aspect of the present invention, the attachment and the brush disk are simply attracted to each other only by the magnetic force. Therefore, the brush disk can be removed from the attachment relatively easily by hand.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a dressing apparatus having a dresser;

FIG. 2 is a cross-sectional view of the dresser;

FIG. 3 is a plan view of an attachment;

FIG. 4 is a bottom view of the attachment;

FIG. 5 is a cross-sectional view taken along line A-A of FIG. 3;

FIG. 6 is a cross-sectional view taken along line B-B of FIG. 5;

FIG. 7 is a plan view of a disk holder;

FIG. 8 is a cross-sectional view taken along line C-C of FIG. 7;

FIG. 9 is a bottom view of the disk holder;

FIG. 10 is a cross-sectional view taken along line D-D of FIG. 9;

FIG. 11 is a cross-sectional view of a dresser according to another embodiment;

FIG. 12 is a cross-sectional view of a dresser according to still another embodiment;

FIG. 13 is a plan view of a brush disk;

FIG. 14 is a cross-sectional view taken along line E-E of FIG. 13;

FIG. 15 is a bottom view of the brush disk; and

FIG. 16 is a cross-sectional view taken along line F-F of FIG. 15.

DETAILED DESCRIPTION

Embodiments of the present invention will be described below with reference to the drawings. In FIGS. 1 through 16, identical elements are denoted by identical reference numerals, and repetitive descriptions thereof are omitted.

FIG. 1 is a perspective view of a dressing apparatus having a dresser for dressing (or conditioning) a polishing pad. As shown in FIG. 1, a polishing pad 2 for use in polishing of a substrate, such as a wafer, is attached to a polishing table 1. The polishing pad 2 is rotated in unison with the polishing table 1 by a table motor 7, which is coupled to the polishing table 1. The wafer is polished by being pressed against the rotating polishing pad 2.

A dressing apparatus 9 includes a dresser 10 which is brought into sliding contact with the polishing pad 2, a dresser shaft 13 to which the dresser 10 is coupled, a pneumatic cylinder 16 mounted to an upper end of the dresser shaft 13, and a dresser arm 17 for rotatably supporting the dresser shaft 13. The dresser 10 has a lower surface serving as a dressing surface 10 a that is formed by abrasive grains (e.g., diamond particles). The pneumatic cylinder 16 is disposed on a support base 20 which is supported by columns 19. These columns 19 are fixedly mounted to the dresser arm 17.

The dresser arm 17 is actuated by a motor (not shown) to pivot on a pivot shaft 22. The dresser shaft 13 is rotated about its own axis by a motor (not shown), thus rotating the dresser 10 about the dresser shaft 13 in a direction indicated by arrow. The pneumatic cylinder 16 serves as an actuator for moving the dresser 10 vertically through the dresser shaft 13 and for pressing the dresser 10 against the surface of the polishing pad 2 at a predetermined force.

Dressing of the polishing pad 2 is performed as follows. The dresser 10 is rotated about the dresser shaft 13, and at the same time pure water is supplied from a pure water supply nozzle (not shown) onto the polishing pad 2. In this state, the dresser 10 is pressed against the polishing pad 2 by the pneumatic cylinder 16 to place the dressing surface 10 a in sliding contact with the polishing pad 2. The dresser arm 17 pivots around the pivot shaft 22 to cause the dresser 10 to oscillate in a radial direction of the polishing pad 2. In this manner, the dresser 10 scrapes the polishing pad 2 to thereby dress (i.e., restore) the surface of the polishing pad 2.

FIG. 2 is a cross-sectional view of the dresser 10. The dresser 10 includes an attachment 30 secured to the dresser shaft 30, a disk holder 50 removably mounted to the attachment 30 by a magnetic force, and a dresser disk 70 removably mounted to the disk holder 50. The attachment 30 is removably secured to the lower end of the dresser shaft 13 by screws 31.

FIG. 3 is a plan view of the attachment 30. FIG. 4 is a bottom view of the attachment 30. FIG. 5 is a cross-sectional view taken along line A-A of FIG. 3. FIG. 6 is a cross-sectional view taken along line B-B of FIG. 5. The attachment 30 has an annular flange 32 and a cylindrical protrusion 33. The protrusion 33 is located at a center of the flange 32 and projects downwardly. The flange 32 has through-holes 32 a formed therein into which the screws 31 are inserted.

A plurality of magnets 35 are embedded in the flange 32. These magnets 35 are arranged around the center of the dresser 10. in the example shown in FIG. 3, twelve magnets 35 are provided. The magnets 35 are arrayed such that magnetic poles of adjacent two of the magnets 35 are different from each other. FIG. 3 shows one example of the array of the magnets 35, and the present invention is not limited to this example shown in FIG. 3.

In FIG. 3, the magnets 35 constitute a plurality of (four in FIG. 3) groups 36, Which are arranged at equal intervals around the center of the dresser 10. These groups 36 are spaced by a predetermined distance, with the through-hole 32 a located between the adjacent groups 36. Each of the groups 36 is constituted by three magnets 35 that are arranged such that south pole and north pole alternate with each other. In the example shown in FIG. 3, the magnets 35 of each group 36 are arrayed in the order of south pole, north pole, and south pole. The magnets 35 of each of the groups 36 are arrayed in the same order. Specifically, each of all the groups 36 is constituted by three magnets 35 that are arrayed in the order of south pole, north pole, and south pole. The present invention, however, is not limited to this magnet arrangement. Each of the groups 36 may he constituted by more than three magnets 35. The magnet 35 may preferably he neodymium magnet.

FIG. 7 is a plan view of the disk holder 50. FIG. 8 is a cross-sectional view taken along line C-C of FIG. 7, FIG. 9 is a bottom view of the disk holder 50. FIG. 10 is a cross-sectional view taken along line D-D of FIG. 9. The disk holder 50 is a disk-shaped member that is larger in diameter than the attachment 30. The disk holder 50 has two circular recesses 51, 52 formed centrally in an upper surface of the disk holder 50. The recesses 51, 52 form a stepped structure. The flange 32 of the attachment 30 is housed in the first-stage recess 51., while the protrusion 33 of the attachment 30 is housed in the second-stage recess 52. The recess 51 has a bottom surface with holes 54 formed therein for receiving respective heads of the screws 31.

A plurality of magnets 56 are embedded in the disk holder 50. These magnets 56 are arranged around the center of the dresser 10. In the example shown in FIG. 9 twelve magnets 56 are provided. These magnets 56 are arrayed such that magnetic poles of adjacent two of the magnets 56 are different from each other. FIG. 9 shows one example of the array of the magnets 56, and the present invention is not limited to this example shown in FIG. 9.

In FIG. 9, the magnets 56 constitute a plurality of (four in FIG. 9) groups 57, which are arranged at equal intervals around the center of the dresser 10. The groups 57 are spaced by a predetermined distance. Each of the groups 57 is constituted by three magnets 56 that are arrayed such that south pole and north pole alternate with each other. In the example shown in FIG. 9, the magnets 56 of each group 57 are arrayed in the order of north pole, south pole, and north pole. The magnets 56 of each of the groups 57 are arrayed in the same order. Specifically, each of all the groups 57 is constituted by three magnets 56 arrayed in the order of north pole, south pole, and north pole. The present invention, however, is not limited to this magnet arrangement. Each of the groups 57 may be constituted by more than three magnets 56.

As shown in. FIG. 2, the magnets 56 are located so as to face the magnets 35 of the attachment 30, thus attracting these magnets 35. Therefore, the disk holder 50 is removably attached to the attachment 30 by a magnetic force (i.e., an attractive force) generated between the magnets 35, 56. The magnets 56 may preferably he neodymium magnets.

As shown in FIGS. 3 and 9, since the south pole and the north pole alternate with each other, the attractive force acting between the attachment 30 and the disk holder 50 is intensified. Moreover, when a torque is applied from the attachment 30 to the disk holder 50, each magnet repels the adjacent magnet. Therefore, a relative position of the attachment 30 and the disk holder 50 is unlikely to change, and the magnets can thus exert strong coupling forces. In the example shown in FIGS. 3 and 9, the magnetic force (the attractive force) generated between the confronting magnet groups 36, 57 makes it easy to set the disk holder 50 on the attachment 30, so that a user finds it easy to use the dresser 10.

In the example shown in FIG. 3, the groups 36, each having an S-N-S-pole array, are arranged at equal intervals in the circumferential direction. It is preferable to provide a clearance as large as at least one pitch of the array of the magnets 35 between. the adjacent groups 36, as shown in FIG. 3, so that the south pole of one group 36 is not close to the south pole of the other group 36. If the south pole of one group 36 is located close to the south pole of the other group 36, an attractive force may be generated between the north pole of the magnet 56 and the south. pole of the magnet 35 of the attachment 30 when the disk holder 50 is angularly displaced relative to the attachment 30 during dressing of the polishing pad 2, thus causing the disk holder 50 to be further displaced and possibly separating the disk holder 50 from the attachment 30. For the same reason, as shown in FIG, 9, it is preferable to provide a clearance as large as at least one pitch of the array of the magnets 56 between the adjacent groups 57. In the example shown in FIG. 3, the magnets 35 of each group 36 are arranged in the order of the south pole, the north pole, and the south pole, but may be arranged in the order of the north pole, the south pole, and the north pole. In this case, the magnets 56 of each group 57 of the disk holder 50 are arranged in the order of the south pole, the north pole, and the south pole.

A plurality of magnets 58 are embedded in a peripheral portion of the disk holder 50. These magnets 58 serve to secure the dresser disk 70 to the disk holder 50. The dresser disk 70 in this embodiment is made of a magnetic material, and is removably attached to the disk holder 50 by a magnetic force of the magnets 58. The dresser disk 70 has an annular lower surface with diamond abrasive grains fixed thereto. These diamond abrasive grains provide the dressing surface 10 a in an annular shape. The dresser 10 dresses (or conditions) the polishing pad 2 with this dressing surface 10 a.

During dressing of the polishing pad 2, the dresser 10 in its entirety is rotated about the dresser shaft 13, and presses the dressing surface 10 a of the dresser disk 70 against the polishing pad 2. A plurality of (two in the drawings) pins 60 are secured to the lower surface of the disk holder 50. These pins 60 are inserted in recesses 71 (see FIG. 2) formed in the upper surface of the dresser disk. 70. The pins 60 that engage with the recesses 71 can prevent the dresser disk 70 from rotating relative to the disk holder 50 when the dresser disk 70 is dressing the polishing pad 2.

According to the present invention, the attachment 30 and the disk holder 50 are simply attracted to each other by the magnetic force. Therefore, when replacing the dresser 10, the disk holder 50, together with the dresser disk 70, can be removed from the attachment 30 relatively easily by hand. While the dresser disk 70 is made of a magnetic material in the above-discussed example, the present invention, can also be applied to a dresser 10 having a dresser disk 70 made of a nonmagnetic material,

FIG. 11 is a cross-sectional view of a dresser 10 according to another embodiment. A dresser disk 70 of this embodiment is made of a nonmagnetic material. The dresser disk 70 is secured to the disk holder 50 by a plurality of screws 73. By removing these screws 73, the dresser disk 70 can be separated from the disk holder 50. Other structural details are the same as those of the above embodiment, and their repetitive descriptions are omitted.

FIG. 12 is a cross-sectional view of a dresser 10 according to still another embodiment. The dresser 10 of this embodiment is a brush. dresser having a dressing surface 10 a constituted by a brush. Structural details of this embodiment which will not be described particularly are the same as those of the above embodiment, and their repetitive descriptions are omitted. The dresser 10 shown in FIG 12 does not have the dresser disk 70, but has a brush disk 80 instead. This brush disk 80 has a structure similar to the disk holder 50 in the above-discussed embodiment.

FIG. 13 is a plan view of the brush disk 80. FIG. 14 is a cross-sectional view taken along line E-E of FIG. 13. FIG. 15 is a bottom view of the brush disk 80. FIG. 16 is a cross-sectional view taken along line F-F of FIG. 15. The brush disk 80 has two circular recesses 81, 82 formed centrally in an upper surface thereof. The recesses 81, 82 form a stepped. structure. The flange 32 of the attachment 30 is housed in the first-stage recess 81, while the protrusion 33 of the attachment 30 is housed in the second-stage recess 82. The recess 81 has a bottom surface with holes 84 formed therein for receiving the respective heads of the screws 31. The brush disk 80 has a lower surface with a brush (not shown) implanted thereon. This brush provides the dressing surface 10 a.

A plurality of magnets 86 are embedded in the brush disk 80. These magnets 86 are arranged around the center of the dresser 10. In the example shown in FIG. 15, twelve magnets 86 are provided. The magnets 86 are arrayed such that magnetic poles of adjacent two of the magnets 86 are different from each other. FIG. 15 shows one example of the array of the magnets 86, and the present invention is not limited to the example shown in FIG. 15. In FIG. 15, the magnets 86 constitute a plurality of (four in FIG. 15) groups 87 that are arranged at equal intervals around the center of the dresser 10. The groups 87 are spaced by a predetermined distance. This distance corresponds to at least one pitch of the array of the magnets 86. The arrangement of the magnets 86 in each group 87 is the same as the arrangement of the magnets 56 shown in FIG. 9. The magnets 86 are located so as to face the magnets 35 of the attachment 30, thus attracting the magnets 35. Therefore, the brush holder 80 is removably attached to the attachment 30 by the magnetic force i.e., the attractive force) generated between the magnets 35, 86. The magnets 86 may preferably be neodymium magnets.

With the above-discussed structure, the dresser 10 dresses the polishing pad 2 by placing the dressing surface 10 a, which is constituted by the brush, in sliding contact with the polishing pad 2. The attachment 30 and the brush disk 80 are simply attracted to each other by the magnetic force. Therefore, when replacing the dresser 10, the brush disk 80 can be removed from the attachment 30 relatively easily by hand.

The previous description of embodiments is provided to enable a person skilled in the art to make and use the present invention. Moreover, various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles and specific examples defined herein may be applied to other embodiments. Therefore, the present invention is not intended to he limited to the embodiments described herein but is to be accorded the widest scope as defined by .imitation of the claims. 

What is claimed is:
 1. A dresser for dressing a polishing pad, comprising: an attachment secured to a dresser shaft for rotating the dresser; a disk holder removably attached to the attachment by a magnetic force; and a dresser disk removably attached to the disk holder, the dresser disk having a dressing surface, wherein each of the attachment and the disk holder has magnet for generating the magnetic force.
 2. The dresser according to claim 1, wherein the magnet comprises a plurality of magnets arranged around a center of the dresser, and an arrangement of the plurality of magnets are such that magnetic poles of adjacent two of the magnets are different from each other.
 3. The dresser according to claim 2, wherein: the plurality of magnets constitute a plurality of groups arranged at equal intervals around the center of the dresser; each of the groups includes at least three magnets arrayed such that north pole and south pole alternate with each other; and an arrangement of the at least three magnets is the same in all of the plurality of groups.
 4. The dresser according to claim 1, wherein the attachment is removably secured to the dresser shaft.
 5. The dresser according to claim 1, wherein the dresser disk is removably attached to the disk holder.
 6. The dresser according to claim 5, wherein the dresser disk is attached to the disk holder by a magnetic force.
 7. The dresser according to claim 5, wherein the dresser disk is attached to the disk holder by a screw
 8. A dresser for dressing a polishing pad, comprising: an attachment secured to a dresser shaft for rotating the dresser; and a brush disk removably attached to the attachment by a magnetic forces, the brush disk having a dressing surface, wherein each of the attachment and the brush disk has magnet for generating the magnetic three.
 9. The dresser according to claim 8, wherein the magnet comprises a plurality of magnets arranged around a center of the dresser, and an arrangement of the plurality of magnets are such that magnetic poles of adjacent two of the magnets are different from each other.
 10. A dresser according to claim 9, wherein: the plurality of magnets constitute a plurality of groups arranged at equal intervals around the center of the dresser; each of the groups includes at least three magnets arrayed such that pale and south pole alternate with each other; and an arrangement of the at least three magnets is the same in all of the plurality of groups.
 11. The dresser according to claim 8, wherein the attachment is removably secured to the dresser shaft. 